Abstract
The P-branch of methane's nu(3) band is probed to carry out an extensive study of the 2905-2908 cm(-1) infrared spectral region. Absolute line intensities as well as N-2-, O-2-, H-2-, He-, Ar- and CO2-broadening coefficients are determined for nine transitions at room temperature. Narrowing parameters due to the Dicke effect have also been investigated. A narrow emission line-width (similar to 0.0001 cm(-1)) difference-frequency-generation (DFG) laser system is used as the tunable light source. To retrieve the CH4 spectroscopic parameters, Voigt and Galatry profiles were used to simulate the measured line shape of the individual transitions. (C) 2014 Elsevier Ltd. All rights reserved.